The invention relates to a method of manufacture of ceramic materials; it has particularly beneficial application to a method of manufacture for ceramic materials containing a finely dispersed second phase within an otherwise homogeneous microstructure such as superconductors containing a flux pinning phase.
Techniques relying on solidification of a melt are widely used in the manufacture of ceramics, ranging from, at the simplest, solidification of a crucible-contained melt, to more refined techniques such as the melt textured growth process. There is a general desire in many cases to ensure that the ceramic solidifies with a homogeneous microstructure. Additionally, problems arise during solidification in those ceramic materials which rely on an evenly-dispersed second phase within the microstructure to confer a particular desired property.
An example of this problem is encountered during the manufacture of a large homogeneous lump of the Yttrium Barium Copper Oxide 123 (YBCO-123) phase high temperature superconductor which contains a second phase of YBCO-211 material the second phase as a fine dispersion of flux pinning centres. At present it is difficult to control the distribution and particle size of the YBCO-211 phase which acts to pin the magnetic flux lines within the material. An enhanced homogeneity of microstructure and more even distribution of pinning centres would enhance the effectiveness of magnetic flux pinning itself, resulting in materials with enhanced critical current density and enhanced repulsion of external magnetic fields.